Coupling

ABSTRACT

A coupling for resilient interconnection of two objects, especially a wheel axle housing and a chassis of a vehicle. The coupling comprises an elongated supporting piece ( 50 ), which extends in a longitudinal direction and two end attachment portions ( 52, 54 ) and a central portion ( 56 ). The coupling also comprises an elastic element ( 60 ), which is arranged around the central portion ( 56 ) and has an approximately cylindrical outer surface ( 64 ) and two end surfaces ( 68, 70 ). The coupling further comprises a first and a second abutment member ( 82, 84 ), where the first abutment member ( 82 ) has a bottom ( 90 ) and a tubular portion ( 86 ), which is fixed to the bottom ( 90 ) and has an open portion and a cylindrical inner surface ( 98 ). The bottom has a trough-going hole ( 106 ) through which one end attachment portion ( 52 ) can extend. The second abutment member ( 84 ) has a hole ( 108 ) through which the second end attachment portion ( 54 ) can extend. The abutment members ( 82, 84 ) are arranged to be interconnected in order to enclose the element. According to the invention the second abutment member ( 84 ) is designed in a similar manner to the first abutment member ( 82 ), end surfaces ( 94, 96 ) of the open end portions being arranged to abut against each other.

BACKGROUND OF THE INVENTION

The invention relates to a coupling for resilient interconnection of twoobjects, especially a wheel axle housing and a chassis of a vehicle,comprising

an internal coupling device comprising a supporting piece, which extendsin an axial direction and has an axial supporting piece portion,

a rubber-elastic element, which is arranged round the supporting pieceportion and has an axially extending outer surface and two substantiallyradially extending end surfaces, and

an external coupling device comprising two, approximately cup-shapedabutment members with a tubular wall portion and a bottom portiondefining an inner portion of the abutment member, where each wallportion has an inner surface arranged to extend along and radiallyoutside respective end portions of the outer surface of the element, theend of the wall portion facing away from the bottom has an end surface,and an inside of each bottom portion facing the inner portion of theabutment member are each arranged to abut against an end surface of theelement for axial compression thereof, while the abutment members arepushed towards each other.

In U.S. Pat. No. 3,030,132 a coupling is disclosed where a body of arubber-elastic material is cast between coupling devices or membersduring the actual assembly of the coupling. In order to ensure that thematerial is adequately compressed, during the casting process a recessis formed in the body while the cup members are kept at a correctdistance apart. This is a laborious method, which is unsuitable formodern, fast serial production of vehicles. There is no indication ofhow a correct centring of the two cup members relative to each other isachieved during casting. A correct relative positioning of the cupmembers and the internal ball surface also seems to be important inorder to ensure that the rubber-elastic material is not pinched betweenthe cup members or that this material completely fills the space betweenthe cup members and the interior ball surface 1. This is also importantto ensure that the coupling obtains the correct spring characteristic.

U.S. Pat. No. 6,231,264 illustrates a bearing device for a torque rodwhere an intermediate sleeve may be provided inside eyelets forming endportions of arms. In the intermediate sleeve is provided a bearingsleeve. The eyelets are not arranged to provide an axial compression ofthe bearing sleeve. The intermediate sleeve is only provided in order tocreate an axially fixed connection between the bearing sleeve and theeyelets, since the intermediate sleeve may be axially secured to thebearing sleeve on one side and on the other side to the eyelets via snaprings. The function of the intermediate sleeve is not for centring theeyelets or for counteracting the penetration of material of the bearingdevice between the eyelets, and it has a row of circular grooves thatweaken it.

In U.S. Pat. No. 5,649,719 an assembly is illustrated comprising a wheelaxle housing and a chassis of a vehicle, and a coupling of theabove-mentioned type for interconnecting the wheel axle housing and thechassis. FIG. 1 is a perspective view of the assembly, where componentshave been separated from one another, and FIG. 2 illustrates alongitudinal section through the coupling.

As illustrated in FIG. 1, a first end portion 6, 8 of two arms 2, 4 iseach connected with a longitudinal frame beam 10 of a vehicle. Secondend portions of each arm 2, 4 converge at a coupling 12 located aboveand in front of a wheel axle housing 14, connecting the arms 2, 4 to thewheel axle housing via a bracket 16.

As illustrated in FIG. 2, the coupling 12 comprises an internal couplingdevice with an elongated supporting piece 20 with end attachmentportions 22, 24 via which the supporting piece can be attached to thewheel axle housing, and a central portion 26, which carries arubber-elastic element 28.

The element 28 is radially enclosed by an external coupling device,which is fixed to the arms 2, 4 and comprises a first abutment member 30with a bottom or shoulder 32, and a second abutment member 34, providedin the form of a ring. This ring 34 may be inserted in the firstabutment member 30 and prevented from being moved out of it by means ofa snap ring 36, which is arranged for insertion in a groove in the firstabutment member 30. The shoulder 32 and the ring 34 are arranged to abutagainst respective opposite end portions 38, 40 of the element 28. Inaddition to the ring 34, the known coupling comprises an additional ring42, which is arranged to abut against the shoulder 32, for extra supportof the element 28 axially, i.e. in the supporting piece's longitudinaldirection.

During operation the coupling is influenced by substantial forces in itslongitudinal direction as well as in its transverse direction. There istherefore a need for extremely strong and hence expensive rings, whichmay have to be forged from steel. When the coupling is assembled, theelement 28 is compressed axially by the ring 34 being forced axially bymeans of a separate tool in the direction of the shoulder 30 or theadditional ring 42, whereupon the snap ring 36 is inserted in the grooveby expanding radially therein. Compression stresses are therebyadvantageously created in the element. During this process it is vitalfor the snap ring 36 to come into a correct engagement with the groovein order to ensure that the snap ring 36 will not be forced out of thegroove under the influence of the highly fluctuating stresses on thecoupling 12 during operation of the vehicle.

The object of the invention is to provide a coupling of theabove-mentioned type, which is encumbered to a lesser extent by theabove-mentioned drawbacks.

SUMMARY OF THE INVENTION

A coupling for resilient interconnection of two objects, especially awheel axle housing and a chassis of a vehicle is provided, comprising aninternal coupling device comprising a supporting piece, which extends inan axial direction and has an axial supporting piece portion, arubber-elastic element, which is arranged around the supporting pieceportion and has an axially extending outer surface and two substantiallyradially extending end surfaces, and an external coupling devicecomprising two, approximately cup-shaped abutment members with a tubularwall portion and a bottom portion defining an inner portion of theabutment member, where each wall portion has an inner surface arrangedto extend along and radially outside respective end portions of theouter surface of the element, the end of the wall portion facing awayfrom the bottom has an end surface, and an inside of each bottom portionfacing the inner portion of the abutment member are each arranged toabut against an end surface of the element for axial compressionthereof, while the abutment members are pushed towards each other,characterized in that between the wall portions and the element anaxially extending sleeve is mounted for relative centering of theabutment members and for counteracting the penetration of portions ofthe element between the end surfaces of the wall portions during theaxial compression of the element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional coupling forinterconnecting a wheel axle housing and a chassis.

FIG. 2 is a longitudinal section through the coupling.

FIG. 3 illustrates a longitudinal section through a first embodiment ofa coupling according to the invention, where two abutment members of thecoupling rest against end portions of an elastic element, but do notcompress it axially.

FIG. 4 illustrates a longitudinal section similar to that illustrated inFIG. 3, but where the element has been compressed and end surfaces ofthe abutment members abut against each other.

FIG. 5 illustrates a longitudinal section through a second embodiment ofa coupling according to the invention, where a sleeve is mounted betweenthe element and two abutment members of the coupling, and the abutmentmembers rest against end portions of an elastic element, but do notcompress it axially.

FIG. 6 illustrates a longitudinal section similar to that illustrated inFIG. 5, but where the element has been compressed and end surfaces ofthe abutment members abut against each other.

FIG. 7 illustrates a longitudinal section through a third embodiment ofa coupling according to the invention, where a sleeve and two discs aremounted between the element and two abutment members of the coupling,where the abutment members of the coupling rest against end portions ofan elastic element via the discs, but do not compress it axially.

FIG. 8 illustrates the area indicated by VIII in FIG. 7 on a largerscale.

FIG. 9 illustrates a longitudinal section similar to that illustrated inFIG. 7, but where the element has been compressed and end surfaces ofthe abutment members abut against each other.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in greater detail with reference toFIGS. 3-9, which schematically illustrate embodiments of the couplingaccording to the invention.

For the different embodiments of the coupling according to theinvention, identical reference numerals are employed for correspondingcomponents and portions.

As illustrated in FIGS. 3 and 4 a first embodiment of a couplingaccording to the invention comprises an internal coupling deviceprovided in the form of an elongated supporting piece 50 with two endportions or end attachment portions 52, 54, which are arranged forreleasable, fixed connection with a wheel axle housing (not shown). Thesupporting piece 50 extends in a longitudinal direction and has acentral portion or supporting piece portion 56, which is located betweenthe end portions 52, 54 and may have a radial extension 58.

The supporting piece's central portion 56 carries a rubber-elasticelement 60 provided approximately in the form of a sleeve, a centralportion 62 thereof extending in the longitudinal direction having acylindrical outer surface 64 with a cylindrical axis 66. The element hasend surfaces 68, 70 facing axially away from each other and extendingradially or conically from the ends of the cylindrical outer surfacetowards the cylindrical axis 66. The element may also have two endflanges 72, 74, which similarly extend radially or conically towards thecylindrical axis 66, and which may comprise the end surfaces 68, 70. Theextension 58 of the supporting piece may prevent an axial, relativemotion of the supporting piece 50 and the element 60. Instead or inaddition the element 60 may be attached to the supporting piece 50 inanother way, e.g. by adhesion or vulcanising.

Radially outside the rubber-elastic element 60 an external couplingdevice 80 is provided comprising two abutment members 82, 84. These maybe separate components that can be arranged to be attached to therespective arms 2, 4 (FIG. 1) via which the coupling is attached to theframe beams 10, or the abutment members 82, 84 and the arms 2, 4 may bemanufactured in one piece, e.g. by forging.

The abutment members 82, 84 are substantially cup-shaped, having tubularwall or side portions or tubular portions 86, 88, one end portion ofwhich is connected to respective end bottoms or bottoms 90, 92. Theother end portion of the tubular portions 86, 88 is open and has endsurfaces 94, 96. The tubular portions 86, 88 also have a cylindricalinner surface 98, 100, whose diameter is adapted to the diameter of thecylindrical outer surface 64 of the rubber-elastic element 60. Thebottoms have an inside 102, 104, whose shape is adapted to suit the endsurfaces 68, 70 of the element 60. Each bottom 90, 92 has a central hole106, 108, whose diameter is preferably larger than the transversedimension of the supporting piece's end portions 52, 54.

As illustrated in FIG. 3, the distance between the bottoms' inside 102,104 and the respective end surfaces 94, 96 of the tubular portions 86,88 is indicated by LR.

It is also clear from this figure that the distance LE between the endsurfaces 68, 70 of the element 60 is greater than 2×LR, i.e. there is agap with a width corresponding to LE−2×LR=LS between the tubularportions' end surfaces 94, 96 when the insides 102, 104 of the abutmentportions' bottoms abut against the element's 60 end surfaces 68, 70.

Axially through the abutment members there are provided holes for screws116 which are illustrated only by their centre lines in FIG. 3.

When assembling the coupling, the supporting piece's 50 end attachmentportions 52, 54 are passed into the holes 106, 108 of the respectiveabutment members 82, 84 until the element's end surfaces 68, 70 comeinto abutment against the bottoms' respective insides 102, 104 asillustrated in FIG. 3. The screws 116 are then tightened until theabutment members' end surfaces 94, 96 come into abutment with eachother. The element 60 is thereby deformed, and material thereof can bepushed out through the holes 106, 108.

FIGS. 5 and 6 illustrate a second embodiment of a coupling according tothe invention.

In the case of this coupling, between the bottoms 90, 92 of the abutmentmembers 82, 84 and between the abutment members' cylindrical innersurfaces 98, 100 and the element's cylindrical outer surface 64 there isprovided a tubular sleeve 120 with length LH. This length is slightlyless than the total length of the abutment members' tubular portion 86,88, i.e. LH<2×LR. There is therefore no danger that this sleeve 120 willbe pinched between the bottoms 90, 92 when the abutment members' endsurfaces 94, 96 abut against each other. When the element 60 is notcompressed, an annulus 122, 124 is formed at the ends of the sleeve.This sleeve prevents the material of the element from becoming pinchedbetween the abutment member's end surfaces 94, 96. By designing thesleeve with an appropriate length, the size of the annuli 122, 124 isadapted in such a manner that the material of the element can extendunhindered into the annuli 122, 124 without preventing the end surfaces94, 96 from coming into abutment with each other.

FIGS. 7-9 illustrate a third embodiment of a coupling according to theinvention.

This embodiment resembles the embodiment according to FIGS. 5 and 6, butin this third embodiment an additional body is provided which may be inthe form of a platelike disc or ring 130, 132, between the bottoms'insides 102, 104 and the respective opposite end surfaces 68, 70 of theelement 60. The thickness of the disc near the sleeve 120 is indicatedby reference letter T. The length of the sleeve can hereby be greaterthan the sum of the element's length and this disc thickness, i.e.LH>LE+T. In addition LH<2×LR can apply as previously. One end of thesleeve can thereby abut against the inside 104 of one bottom 92 and onedisc 132, while simultaneously overlapping a portion of the opposite endsurface of the other disc 130 at a point 134 according to FIG. 8 whenthe abutment members 82, 84 are not compressing the element 60. At thesame time LS<T can apply.

When the abutment members are compressed during assembly of thecoupling, the material of the element 60 is thereby prevented frompenetrating and becoming pinched in the small annulus 136 that isdefined by the sleeve 120, the disc 130 and the abutment member 82.

The sleeve 120 may be connected to the element 60 over the whole or partof its length. The relative positions of the sleeve and the element canthereby be guaranteed and the number of separate parts of the couplingreduced.

Since the discs 130, 132 are supported against the abutment members 82,84, the discs can be manufactured much more cheaply than in the priorart by stamping a plate instead of forging. The invention permits theabutment members to be fabricated from light metal, since there is noneed for a highly loaded groove to be manufactured for a snap ring. Atypical thickness for the discs may be 2 mm. The sleeve also has animportant function in that it ensures a relative centring of theabutment members during assembly. Even though it is stated above thatthe abutment members can be screwed together, with the result that thereis no need for any extra tool such as a press for joining them, it willbe appreciated that the abutment members may be interconnected by meansof welding. A drawback with this solution is the difficulties that ariseif element 60 has to be replaced.

The abutment members are preferably identical, but it will be understoodthat their dimensions may be different provided they can beinterconnected and act as indicated above.

The coupling according to the invention is described above in connectionwith interconnection of a wheel axle housing and a chassis of a vehicle,but it will be understood that the coupling may be employed in any kindof device where two objects have to be interconnected, where they have acertain amount of relative freedom of movement with six degrees offreedom.

1. A coupling for resilient interconnection of two objects, comprising:an internal coupling device having a supporting piece, which extends inan axial direction and has an axial supporting piece portion; arubber-elastic element, which is arranged around the supporting pieceportion and has an outer surface parallel to the axial direction and twoend surfaces extending substantially radially to the axial direction;and an external coupling device comprising two approximately cup-shapedabutment members, each member having a tubular wall portion and a bottomportion defining an inner portion of the abutment member, where eachtubular wall portion has an inner surface arranged to extend along andradially outside a respective end portion of the outer surface of therubber-elastic element, and an end of each tubular wall portion facingaway from the bottom portion has an end surface, wherein the endsurfaces of the tubular wall portions abut each other when the abutmentmembers are pushed towards each other, wherein between the tubular wallportions and the rubber-elastic element, an axially extending sleeve ismounted for relative centering of the abutment members and forcounteracting penetration of portions of the rubber-elastic elementbetween the end surfaces of the tubular wall portions during axialcompression of the rubber-elastic element.
 2. The coupling according toclaim 1, wherein between the inside wall of each bottom portion and eachend surface of the rubber-elastic element, an annular disc is mounted.3. The coupling according to claim 2, wherein the rubber-elastic elementis securely connected to the annular discs.
 4. The coupling according toany of claims 1, 2, or 3, wherein the rubber-elastic element is securelyconnected to the supporting piece.
 5. The coupling according to claim 1,wherein the sleeve is securely connected to the rubber-elastic elementover the whole or a part of its length.